Shoppers who were on the first floor of the mall, and especially those who were in the Best Buy and AT&T stores were at the greatest risk of exposure, officials said.

A young child with measles visited those stores on Super Bowl Sunday, Rockland County Health Commissioner Dr. Patricia Ruppert said. “The case involves an individual who has returned from traveling abroad and was not immunized against measles.”

Measles is a highly contagious respiratory disease caused by a virus and is spread by contact with an infected person. The disease can lead to serious side effects and, in rare cases, death.

So far health officials have only reported this one case but worry the infected child may have exposed an unknown number of people, CBS 2’s Tracee Carrasco reported.

The health department urged anyone who may have symptoms, including a fever and a rash, to call their doctor. Those affected may also experience sensitivity to light.

Symptoms typically appear within 10-12 days, but can occur as late as 18 days after exposure, the health department said.

Health officials said anyone who has received the measles, mumps and rubella vaccine is immune. Those who have not could be at risk.

In addition, officials said anyone who falls under the high-risk category should call their doctor immediately.

Those considered high risk include pregnant women, children under the age of 6 months, those who are immunocompromised or immunosuppressed, or if you have not been vaccinated against the measles.

Pregnant women or anyone who has not been immunized against measles should look for symptoms, call their doctor and avoid contact with others, the health department said.

Those who present symptoms are asked to call their physician, health care provider or emergency room before going for care so that others are not exposed in the waiting room.